Starch consists of a mixture of amylose (15-30% w/w) and amylopectin (70-85% w/w). Amylose consists of linear chains of α-1,4-linked glucose units having a molecular weight (MW) from about 60,000 to about 800,000. Amylopectin is a branched polymer containing α-1,6 branch points every 24-30 glucose units; its MW may be as high as 100 million.
Sugars from starch, in the form of concentrated dextrose syrups, are currently produced by an enzyme catalyzed process involving: (1) liquefaction (or viscosity reduction) of solid starch with an α-amylase into dextrins having an average degree of polymerization of about 7-10, and (2) saccharification of the resulting liquefied starch (i.e. starch hydrolysate) with amyloglucosidase (also called glucoamylase or GA). The resulting syrup has a high glucose content. Much of the glucose syrup that is commercially produced is subsequently enzymatically isomerized to a dextrose/fructose mixture known as isosyrup.
α-amylases (EC 3.2.1.1) hydrolyze starch, glycogen, and related polysaccharides by cleaving internal α-1,4-glucosidic bonds at random. For a number of years, α-amylase enzymes have been used for a variety of different purposes, including starch liquefaction, textile desizing, starch modification in the paper and pulp industry, and for brewing. These enzymes can also be used to remove starchy stains during dishwashing and laundry washing. Laundry and dish soils vary greatly in composition and, therefore, in their ability to be effectively and efficiently removed.
Nesterenkonia spp. are Gram-positive bacteria classified as members of the Family Micrococcceae, Suborder Micrococcineae, Order Actinomycetales, Class Actinobacteria. Nesterenkonia xinjianensis, first described in 2004, was isolated from hypersaline soil samples from Xinjiang Province, China (Wen-Jun Li et al. (2004) Int. J. Syst. Evol. Microbiol. 54:837-41). N. xinjiangensis is not recognized as being an amylase-producing bacterium. In fact, the species description of the Type Strain indicates that the organism produces a negative reaction for starch hydrolysis, suggesting that amylases are not produced, or not secreted.